Each title in this series tells the story of a man or woman whose dedication to their chosen cause led to changes that affect all our lives today. Each includes a vivid description of the world in which the famous person lived. In this book, the reader learns that James Watt was a scientific instrument maker who was asked to repair a working model of an early type of steam engine used to pump water out of Cornish tin mines. It was when he set about improving the design, so it would exert more power but use less fuel, and teamed up with a mine owner from Birmingham, that his machines became popular. Despite illness and heartbreak, Watt went on to modify his engine so it could power machines in factories that produced goods, such as cotton. The narrative shows how this ushered in the era of mass-production, while accurate illustration show how Watt's engines work.